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Antarctic circumpolar current transport variability during 2003–05 from GRACE

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dc.contributor.author Zlotnicki, Victor
dc.contributor.author Wahr, John
dc.contributor.author Fukumori, Ichiro
dc.contributor.author Song, Yuhe T.
dc.date.accessioned 2007-08-16T21:13:55Z
dc.date.available 2007-08-16T21:13:55Z
dc.date.issued 2007-02
dc.identifier.citation Journal of Physical Oceanography, February 2007 (Vol. 37, No. 2, 230-244) en
dc.identifier.clearanceno 06-2279
dc.identifier.uri http://hdl.handle.net/2014/40371
dc.description.abstract Gravity Recovery and Climate Experiment (GRACE) gravity data spanning January 2003–November 2005 are used as proxies for ocean bottom pressure (BP) averaged over 1 month, spherical Gaussian caps 500 km in radius, and along paths bracketing the Antarctic Circumpolar Current’s various fronts. The GRACE BP signals are compared with those derived from the Estimating the Circulation and Climate of the Ocean (ECCO) ocean modeling–assimilation system, and to a non-Boussinesq version of the Regional Ocean Model System (ROMS). The discrepancy found between GRACE and the models is 1.7 cm<subscript>H2O (1 cm<subscript>H2O ~ 1 hPa), slightly lower than the 1.9 cmH2O estimated by the authors independently from propagation of GRACE errors. The northern signals are weak and uncorrelated among basins. The southern signals are strong, with a common seasonality. The seasonal cycle GRACE data observed in the Pacific and Indian Ocean sectors of the ACC are consistent, with annual and semiannual amplitudes of 3.6 and 0.6 cmH2O (1.1 and 0.6 cm<subscript>H2O with ECCO), the average over the full southern path peaks (stronger ACC) in the southern winter, on days of year 197 and 97 for the annual and semiannual components, respectively; the Atlantic Ocean annual peak is 20 days earlier. An approximate conversion factor of 3.1 Sv (Sv equiv 106 m3 sˉ¹) of barotropic transport variability per cm<subscript>H2O of BP change is estimated. Wind stress data time series from the Quick Scatterometer (QuikSCAT), averaged monthly, zonally, and over the latitude band 40°– 65°S, are also constructed and subsampled at the same months as with the GRACE data. The annual and semiannual harmonics of the wind stress peak on days 198 and 82, respectively. A decreasing trend over the 3 yr is observed in the three data types. en
dc.description.sponsorship NASA/JPL en
dc.format.extent 1314286 bytes
dc.format.mimetype application/pdf
dc.language.iso en_US en
dc.publisher American Meteorological Society en
dc.subject Gravity Recovery and Climate Experiment (GRACE) en
dc.subject Antarctic currents en
dc.title Antarctic circumpolar current transport variability during 2003–05 from GRACE en
dc.type Article en


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